Of course it is (if you by musical instruments mean actual hardware/acoustic instruments and not software instruments). I would start with Garageband, which is free in the app store, or maybe even pre-installed on your mac. Then go and look at a couple of tutorials. Logic might be the way to go in the future, but as it is quite expensive it might be overkill to start with. You can always import your Garageband projects into Logic if you decide to upgrade.